Webasto CC8 - System Leak-Testing and Evacuation

4 Installation instructions CC8 roof-top air-conditioning system
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4.14 System leak-testing and evacuation
4.14.1 General
• Moisture and air or other gaseous impurities in the refrigerant circuit cause malfunctions and may damage the air-
conditioning system components. The system therefore must be thoroughly dried and evacuated (for at least
1.5 hours) before it is filled with refrigerant. This not only applies to newly installed air-conditioning systems, but
also to systems that have been repaired if the refrigerant had to be discharged beforehand.
The final vacuum in the system must not exceed the absolute vacuum by more than 0.005 bar. Consequently the
absolute pressure in the system must be ≤ 0.005 bar.
• The absolute pressure indicated on the gauge depends on the ambient atmospheric air pressure. This must be
taken into consideration.
• Refrigerant can escape through the smallest leaks. The refrigeration circuit must therefore be completely sealed.
To prevent any unnecessary refrigerant loss from occurring, we recommend that the system be inspected
repeatedly for leaks during the evacuation process.
• The quick-action stop valves are fixed to the fittings on the refrigerant hoses. The quick-action stop valves for the
discharge and intake lines have different diameters so that the connections cannot be confused.
• An ambient temperature of at least 20°C is required for evacuating and filling the system.
4.14.2 Description of the fittings
The test fittings consist of a intake pressure gauge, a high pressure gauge and a vacuum pressure gauge, as well as
the four ports listed below, all of which can be shut off by means of a stop valve.
Connections/hoses:
LOW Connection for the intake side of the system
– Yellow hose with Low Side quick-action stop valve
HIGH Connection for the discharge side of system
– Red hose with High Side quick-action stop valve
REF Connection for the refrigerant bottles
– Yellow hose with quick-release screw coupling 7/16" UNF
VAC Connection for the vacuum pump
– Yellow hose (thick) with quick-release screw coupling 5/8"
4.14.3 Evacuation
1. Switch on the vacuum pump and evacuate the system for at least 1.5 hours. The absolute pressure achieved must
be at least 0.005 bar.
2. During the evacuation process with the pump running, repeatedly close all valves of the test equipment and check
the pressure gauge readings. If there is no change in the vacuum reading over a period of one minute, you may
assume that there are no leaks in the system. Re-open the valves after each pressure check.
NOTE
A rise in the pressure indicates a leak in the system. In this case, stop the evacuation
process and isolate and seal the leak. Then repeat the evacuation procedure.
3. Close all valves on the test equipment. Switch off the vacuum pump. Leave the system for at least one hour and
then check the vacuum. If vacuum does not change, the system has been evacuated sufficiently and is not leaking.